The first two options use frames to show you the journal text for each day on multiple pages, along with thumbnails of photos taken on that day and a "menu" frame (bottom right) that allows you to navigate among days. You can go to the next page of text by following the link at the bottom of the text, or by clicking on the page numbers in the upper right corner. Clicking on any of the thumbnails along the bottom or right side of the screen brings up a larger view of that photo, along with a caption explaining it. Occasionally, there will be hypertext links to external references (which will all be opened in a separate window), and thumbnails embedded in the journal text; thumbnails with a green border can also be enlarged. A checkbox allows you to control whether enlarged photos replace the text in the journal frame, or appear in a separate browser window.
The last two options have significantly less navigation - you can only move "forward" unless you switch to the combined journal/photo frameset. To switch to the journal/photo frames, click on the "restore frames" link. To switch from the frameset to journal text or photos only, simply open the corresponding frame in a new window (usually done by pressing the right mouse button and selecting that option in your browser).
All of these viewing options except the last one require that you have a version 4.0 or later browser running JavaScript. (Opera 3.5 or later should also be okay.) If you don't have JavaScript available or turned on, you'll only be able to read the journal text, without photos or embedded thumbnails. (Don't have JavaScript and feeling screwed? See the techie details to find out why I did this.)